Bake chicken in a 360 degree F oven until cooked completely through
and golden brown in color.

Meanwhile, in a large pan, heat olive oil. Add garlic, onions, and
mushrooms. Sauté until onions become tender. Add capers, oregano,
and sherry. Once half the sherry has cooked out, add the marinara
sauce and reduce by a third.

On a large platter, place a ring of mashed potatoes just inside the
rim. Place chicken on the potatoes. Top chicken with sauce, serve to
delighted guests and graciously accept their compliments.